For certain reactants, the time for total interaction--complete reaction--is extremely short. Therefore, to avoid undesirable by-products in selected situations, the reactants must be very rapidly and completely mixed. At relatively low flow rates--say in the order of 10 gallons per minute--most prior art mixers do not accomplish complete mixing of reactants where the reactions are very fast. If the flow rate of the components is increased sufficiently, however, these mixers will produce adequate mixing. Unfortunately, in some situations, an increase in the flow rate is not feasible because of the resultant large pressure drop produced across the mixer.
One type of static mixer known in the art is the Kenics mixer, which is essentially described in U.S. Pat. No. 3,286,992, issued Nov. 22, 1966. This mixer comprises a plurality of curved sheet-like elements longitudinally arranged within a hollow cylindrical tube. The curved elements are in fact short right- and left-hand helices that are welded together and arranged in the tube so that each successive element is curved in the opposite sense with respect to the preceding element. Reactants flowing through the mixer are divided at the leading edge of each element. As the flow divides, it follows the channel formed by each element to be divided again at the leading edge of each successive element. By dividing the fluid flow in this manner over a number of elements, mixing of the fluid components may be accomplished.
Another mixer used heretofore is the Koch mixer. The operation of this mixer is described in detail in an article by N. R. Schott, B. Weinstein, and D. LaBombard, "Motionless Mixers in Plastic Processing", Chemical Engineering Progress, Vol. 71, No. 1, January 1975. The mixing element of the Koch mixer is an appropriately-shaped assembly that contains a large number of parallel, corrugated metal sheets. The corrugation angle of adjacent layers in the element is reversed relative to the mixer axis so that inclined corrugations of adjacent sheets intersect to form a multitude of mixing cells. Flow entering a particular mixing cell as one stream is divided into two new streams, each leaving the mixing cell in a different direction. Both flow stream upon arriving at the next corrugation intersection are again each divided and rearranged into two new and different streams, each of which may again be divided and rearranged. Adjacent corrugation elements are also rotated 90.degree. with respect to one another to provide a third dimension to the above-described two dimensional reaction pattern.
Still another mixer described in the above-cited article is the Ross LPD mixer. In this mixer, mixing is accomplished by producing a swirling effect as the fluid components pass through holes in the mixing elements. Adjoining mixing elements are connected together so that a tetrahedral space is formed between them. Each element has four circular holes aligned on a diameter on its face. In passing through each element, the position of the holes is changed so that the diameter on which the holes align is rotated 90.degree. on the opposite face. Thus, by interchanging the sequence of holes in each element, the flow of liquid components is divided to produce mixing.
While the above-described mixers are adequate for reacting coreactants under most conditions, they do not produce adequate mixing where reactants must be rapidly mixed at relatively low flow rates. Accordingly, the reactor of the present invention is particularly suitable for use where two unusually reactive materials are to be mixed. Of course, the reactor of the present invention may be used for reacting most any type of coreactants.